v2.10.1

Add --reactCompat option to cli

CHANGELOG.md

@@ -11,6 +11,55 @@
 
 _Note: Gaps between patch versions are faulty/broken releases._
 
+## 2.10.1
+
+ * **Internal**
+  * Upgrade `core-js` to `0.4.4`.
+ * **New Feature**
+  * Added `--include-regenerator` option to CLI and `includeRegenerator` option to API that includes the regenerator runtime if necessary.
+
+## 2.10.0
+
+ * **New Feature**
+  * Add `classesFastSuper` optional transformer that doesn't support parent getters and prototype changing.
+  * Add `forOfFast` transformer that speeds up `for...of` on arrays but produces more code.
+  * Add `--react-compat` to `bin/6to5`.
+ * **Spec Compliancy**
+  * Disallow setters without a single parameter.
+  * Add `configurable` and `writable` to defined properties.
+  * Use define instead of assignment for class methods.
+ * **Polish**
+  * Fix bin name in `6to5-node --help`.
+  * Fix shorthand `--whitelist` name in `bin/6to5`.
+ * **Internal**
+  * Hot code optimisation of traversal etc thanks to [gaearon](https://github.com/gaearon).
+
+## 2.9.4
+
+ * **Bug Fix**
+  * Support `UpdateExpression`s as `MemberExpression` objects.
+
+## 2.9.3
+
+ * **Bug Fix**
+  * Remove `exportsWildcard` helper in favor of `defaults`.
+
+## 2.9.2
+
+ * **Bug Fix**
+  * Pass `exports` to `exportWildcard` helper to allow for use inside the optional runtime.
+
+## 2.9.1
+
+ * **Bug Fix**
+  * Fix runtime generator breaking the helper inclusion loop.
+
+## 2.9.0
+
+ * **Internal**
+  * Upgrade `acorn-6to5`.
+    * Now supports destructuring shorthand properties.
+
 ## 2.8.1
 
  * **Bug Fix**

Makefile

@@ -71,6 +71,9 @@ publish:
 
 	make test
 
+	read -p "Version: "  version; \
+	npm version $$version --message "v%s"
+
 	make build
 	cp dist/6to5.min.js browser.js
 	cp dist/polyfill.min.js browser-polyfill.js
@@ -79,8 +82,6 @@ publish:
 	node bin/cache-templates
 	test -f templates.json
 
-	read -p "Version: "  version; \
-  npm version $$version --message "v%s"
 	npm publish
 
 	git push --follow-tags

NOTES.md

@@ -7,3 +7,6 @@
  * Remove `allowImportExportEverywhere` option from acorn.
  * Remove this shorthand from playground.
  * Remove `super()` inside non-constructors - add descriptive error message.
+ * Split up ES5 getter/setter transforming and ES6 property methods into separate transformers.
+ * Add autoindentation.
+ * Move `super` transformation from classes into a separate transformer that also supports object expressions.

bin/6to5/index.js

@@ -15,7 +15,7 @@ commander.option("-e, --experimental", "Enable experimental support for proposed
 commander.option("-p, --playground", "Enable playground support");
 
 commander.option("-m, --modules [modules]", "Module formatter type to use [common]", "common");
-commander.option("-w, --whitelist [whitelist]", "Whitelist of transformers to ONLY use", util.list);
+commander.option("-l, --whitelist [whitelist]", "Whitelist of transformers to ONLY use", util.list);
 commander.option("-b, --blacklist [blacklist]", "Blacklist of transformers to NOT use", util.list);
 commander.option("-i, --optional [list]", "List of optional transformers to enable", util.list);
 commander.option("-o, --out-file [out]", "Compile all input files into a single file");
@@ -24,6 +24,8 @@ commander.option("-c, --remove-comments", "Remove comments from the compiled cod
 commander.option("-I, --indent [width]", "Indent width [2]", 2);
 commander.option("-a, --amd-module-ids", "Insert module id in AMD modules", false); // todo: remove in 3.0.0
 commander.option("-m, --module-ids", "Insert module id in modules", false);
+commander.option("-R, --react-compat", "Makes the react transformer produce pre-v0.12 code");
+commander.option("-E, --include-regenerator", "Include the regenerator runtime if necessary", false);
 
 commander.on("--help", function(){
   var outKeys = function (title, obj) {
@@ -99,17 +101,19 @@ if (errors.length) {
 //
 
 exports.opts = {
-  sourceMapName: commander.outFile,
-  experimental:  commander.experimental,
-  playground:    commander.playground,
-  moduleIds:     commander.amdModuleIds || commander.moduleIds,
-  blacklist:     commander.blacklist,
-  whitelist:     commander.whitelist,
-  sourceMap:     commander.sourceMaps || commander.sourceMapsInline,
-  optional:      commander.optional,
-  comments:      !commander.removeComments,
-  runtime:       commander.runtime,
-  modules:       commander.modules,
+  includeRegenerator: commander.includeRegenerator,
+  sourceMapName:      commander.outFile,
+  experimental:       commander.experimental,
+  reactCompat:        commander.reactCompat,
+  playground:         commander.playground,
+  moduleIds:          commander.amdModuleIds || commander.moduleIds,
+  blacklist:          commander.blacklist,
+  whitelist:          commander.whitelist,
+  sourceMap:          commander.sourceMaps || commander.sourceMapsInline,
+  optional:           commander.optional,
+  comments:           !commander.removeComments,
+  runtime:            commander.runtime,
+  modules:            commander.modules,
   format: {
     indent: {
       style:     util.repeat(parseInt(commander.indent))

bin/_6to5-node

@@ -10,29 +10,31 @@ var util       = require("../lib/6to5/util");
 var vm         = require("vm");
 var _          = require("lodash");
 
-commander.option("-e, --eval [script]", "Evaluate script");
-commander.option("-p, --print", "Evaluate script and print result");
-commander.option("-i, --ignore [regex]", "Ignore all files that match this regex when using the require hook");
-commander.option("-x, --extensions [extensions]", "List of extensions to hook into [.es6,.js]");
-commander.option("-r, --experimental", "Enable experimental support for proposed ES7 features");
-commander.option("-g, --playground", "Enable playground support");
-commander.option("-c, --cache", "Cache compiled files and require paths");
+var program = new commander.Command("6to5-node");
+
+program.option("-e, --eval [script]", "Evaluate script");
+program.option("-p, --print", "Evaluate script and print result");
+program.option("-i, --ignore [regex]", "Ignore all files that match this regex when using the require hook");
+program.option("-x, --extensions [extensions]", "List of extensions to hook into [.es6,.js]");
+program.option("-r, --experimental", "Enable experimental support for proposed ES7 features");
+program.option("-g, --playground", "Enable playground support");
+program.option("-c, --cache", "Cache compiled files and require paths");
 
 var pkg = require("../package.json");
-commander.version(pkg.version);
-commander.usage("[options] [ -e script | script.js ] [arguments]");
-commander.parse(process.argv);
+program.version(pkg.version);
+program.usage("[options] [ -e script | script.js ] [arguments]");
+program.parse(process.argv);
 
-if (commander.cache) roadrunner.load();
+if (program.cache) roadrunner.load();
 
 //
 
 to5.register({
-  experimental: commander.experimental,
-  extensions:   commander.extensions,
-  playground:   commander.playground,
-  ignore:       commander.ignore,
-  cache:        commander.cache && roadrunner.get("6to5")
+  experimental: program.experimental,
+  extensions:   program.extensions,
+  playground:   program.playground,
+  ignore:       program.ignore,
+  cache:        program.cache && roadrunner.get("6to5")
 });
 
 //
@@ -41,17 +43,17 @@ var _eval = function (code, filename) {
   code = to5.transform(code, {
     filename: filename,
     blacklist: ["useStrict"],
-    experimental: commander.experimental,
-    playground: commander.playground
+    experimental: program.experimental,
+    playground: program.playground
   }).code;
   return vm.runInThisContext(code, filename);
 };
 
-if (commander.eval) {
-  var result = _eval(commander.eval, "eval");
-  if (commander.print) console.log(result);
+if (program.eval) {
+  var result = _eval(program.eval, "eval");
+  if (program.print) console.log(result);
 } else {
-  if (commander.args.length) {
+  if (program.args.length) {
     // slice all arguments up to the first filename since they're 6to5 args that we handle
     var args = process.argv.slice(2);
 
@@ -77,7 +79,7 @@ if (commander.eval) {
   }
 }
 
-if (commander.cache) roadrunner.save();
+if (program.cache) roadrunner.save();
 
 function replStart() {
   repl.start({

lib/6to5/file.js

@@ -35,8 +35,8 @@ File.helpers = [
   "async-to-generator",
   "interop-require-wildcard",
   "typeof",
-  "exports-wildcard",
-  "extends"
+  "extends",
+  "get"
 ];
 
 File.excludeHelpersFromRuntime = [
@@ -48,21 +48,22 @@ File.normaliseOptions = function (opts) {
   opts = _.cloneDeep(opts || {});
 
   _.defaults(opts, {
-    experimental: false,
-    reactCompat:  false,
-    playground:   false,
-    whitespace:   true,
-    moduleIds:    opts.amdModuleIds || false,
-    blacklist:    [],
-    whitelist:    [],
-    sourceMap:    false,
-    optional:     [],
-    comments:     true,
-    filename:     "unknown",
-    modules:      "common",
-    runtime:      false,
-    code:         true,
-    ast:          true
+    includeRegenerator: false,
+    experimental:       false,
+    reactCompat:        false,
+    playground:         false,
+    whitespace:         true,
+    moduleIds:          opts.amdModuleIds || false,
+    blacklist:          [],
+    whitelist:          [],
+    sourceMap:          false,
+    optional:           [],
+    comments:           true,
+    filename:           "unknown",
+    modules:            "common",
+    runtime:            false,
+    code:               true,
+    ast:                true
   });
 
   // normalise windows path separators to unix

lib/6to5/generation/buffer.js

@@ -61,7 +61,7 @@ Buffer.prototype.space = function () {
 Buffer.prototype.removeLast = function (cha) {
   if (!this.isLast(cha)) return;
 
-  this.buf = this.buf.slice(0, -1);
+  this.buf = this.buf.substr(0, this.buf.length - 1);
   this.position.unshift(cha);
 };
 
@@ -77,10 +77,9 @@ Buffer.prototype.newline = function (i, removeLast) {
     if (this.endsWith("{\n")) i--;
     if (this.endsWith(util.repeat(i, "\n"))) return;
 
-    var self = this;
-    _.times(i, function () {
-      self.newline(null, removeLast);
-    });
+    for (var j = 0; j < i; j++) {
+      this.newline(null, removeLast);
+    }
     return;
   }
 
@@ -115,13 +114,18 @@ Buffer.prototype._push = function (str) {
 };
 
 Buffer.prototype.endsWith = function (str) {
-  return this.buf.slice(-str.length) === str;
+  var d = this.buf.length - str.length;
+  return d >= 0 && this.buf.lastIndexOf(str) === d;
 };
 
 Buffer.prototype.isLast = function (cha, trimRight) {
   var buf = this.buf;
   if (trimRight) buf = util.trimRight(buf);
+  var last = buf[buf.length - 1];
 
-  var chars = [].concat(cha);
-  return _.contains(chars, _.last(buf));
+  if (Array.isArray(cha)) {
+    return _.contains(cha, last);
+  } else {
+    return cha === last;
+  }
 };

lib/6to5/generation/node/index.js

@@ -6,14 +6,19 @@ var t          = require("../../types");
 var _          = require("lodash");
 
 var find = function (obj, node, parent) {
+  if (!obj) return;
   var result;
 
-  _.each(obj, function (fn, type) {
+  var types = Object.keys(obj);
+  for (var i = 0; i < types.length; i++) {
+    var type = types[i];
+
     if (t["is" + type](node)) {
+      var fn = obj[type];
       result = fn(node, parent);
-      if (result != null) return false;
+      if (result != null) break;
     }
-  });
+  }
 
   return result;
 };
@@ -99,7 +104,13 @@ _.each(Node.prototype, function (fn, key) {
   Node[key] = function (node, parent) {
     var n = new Node(node, parent);
 
-    var args = _.toArray(arguments).slice(2);
+    // Avoid leaking arguments to prevent deoptimization
+    var skipCount = 2;
+    var args = new Array(arguments.length - skipCount);
+    for (var i = 0; i < args.length; i++) {
+      args[i] = arguments[i + 2];
+    }
+
     return n[key].apply(n, args);
   };
 });

lib/6to5/generation/node/parentheses.js

@@ -21,6 +21,13 @@ _.each([
   });
 });
 
+exports.UpdateExpression = function (node, parent) {
+  if (t.isMemberExpression(parent) && parent.object === node) {
+    // (foo++).test()
+    return true;
+  }
+};
+
 exports.ObjectExpression = function (node, parent) {
   if (t.isExpressionStatement(parent)) {
     // ({ foo: "bar" });

lib/6to5/generation/position.js

@@ -1,33 +1,27 @@
 module.exports = Position;
 
-var _ = require("lodash");
-
 function Position() {
   this.line = 1;
   this.column = 0;
 }
 
 Position.prototype.push = function (str) {
-  var self = this;
-
-  _.each(str, function (cha) {
-    if (cha === "\n") {
-      self.line++;
-      self.column = 0;
+  for (var i = 0; i < str.length; i++) {
+    if (str[i] === "\n") {
+      this.line++;
+      this.column = 0;
     } else {
-      self.column++;
+      this.column++;
     }
-  });
+  }
 };
 
 Position.prototype.unshift = function (str) {
-  var self = this;
-
-  _.each(str, function (cha) {
-    if (cha === "\n") {
-      self.line--;
+  for (var i = 0; i < str.length; i++) {
+    if (str[i] === "\n") {
+      this.line--;
     } else {
-      self.column--;
+      this.column--;
     }
-  });
+  }
 };

lib/6to5/generation/whitespace.js

@@ -11,15 +11,18 @@ Whitespace.prototype.getNewlinesBefore = function (node) {
   var startToken;
   var endToken;
   var tokens = this.tokens;
+  var token;
+
+  for (var i = 0; i < tokens.length; i++) {
+    token = tokens[i];
 
-  _.each(tokens, function (token, i) {
     // this is the token this node starts with
     if (node.start === token.start) {
       startToken = tokens[i - 1];
       endToken = token;
-      return false;
+      break;
     }
-  });
+  }
 
   return this.getNewlinesBetween(startToken, endToken);
 };
@@ -28,15 +31,18 @@ Whitespace.prototype.getNewlinesAfter = function (node) {
   var startToken;
   var endToken;
   var tokens = this.tokens;
+  var token;
+
+  for (var i = 0; i < tokens.length; i++) {
+    token = tokens[i];
 
-  _.each(tokens, function (token, i) {
     // this is the token this node ends with
     if (node.end === token.end) {
       startToken = token;
       endToken = tokens[i + 1];
-      return false;
+      break;
     }
-  });
+  }
 
   if (endToken.type.type === "eof") {
     return 1;

lib/6to5/runtime-generator.js

@@ -20,7 +20,7 @@ module.exports = function (namespace) {
 
   _.each(File.helpers, function (name) {
     if (_.contains(File.excludeHelpersFromRuntime, name)) {
-      return false;
+      return;
     }
 
     var key = t.identifier(t.toIdentifier(name));

lib/6to5/transformation/modules/_default.js

@@ -217,7 +217,8 @@ DefaultFormatter.prototype._exportSpecifier = function (getRef, specifier, node,
 };
 
 DefaultFormatter.prototype._exportsWildcard = function (objectIdentifier) {
-  return t.expressionStatement(t.callExpression(this.file.addHelper("exports-wildcard"), [
+  return t.expressionStatement(t.callExpression(this.file.addHelper("defaults"), [
+    t.identifier("exports"),
     t.callExpression(this.file.addHelper("interop-require-wildcard"), [objectIdentifier])
   ]));
 };

lib/6to5/transformation/templates/class-super-constructor-call-fast.js

@@ -0,0 +1,5 @@
+(function () {
+  if (SUPER_NAME != null) {
+    SUPER_NAME.apply(this, arguments);
+  }
+});

lib/6to5/transformation/templates/class-super-constructor-call.js

@@ -1,3 +1,3 @@
-if (SUPER_NAME !== null) {
-  SUPER_NAME.apply(this, arguments);
+if (Object.getPrototypeOf(CLASS_NAME) !== null) {
+  Object.getPrototypeOf(CLASS_NAME).apply(this, arguments);
 }

lib/6to5/transformation/templates/exports-wildcard.js

@@ -1,7 +0,0 @@
-(function (obj) {
-  for (var i in obj) {
-    if (exports[i] !== undefined) {
-      exports[i] = obj[i];
-    }
-  }
-})

lib/6to5/transformation/templates/for-of-fast.js

@@ -0,0 +1,13 @@
+for (var LOOP_OBJECT = OBJECT,
+         IS_ARRAY = Array.isArray(LOOP_OBJECT),
+         INDEX = 0,
+         LOOP_OBJECT = IS_ARRAY ? LOOP_OBJECT : LOOP_OBJECT[Symbol.iterator]();;) {
+  if (IS_ARRAY) {
+    if (INDEX >= LOOP_OBJECT.length) break;
+    ID = LOOP_OBJECT[INDEX++];
+  } else {
+    INDEX = LOOP_OBJECT.next();
+    if (INDEX.done) break;
+    ID = INDEX.value;
+  }
+}

lib/6to5/transformation/templates/get.js

@@ -0,0 +1,23 @@
+(function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent, property, receiver);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+
+    if (getter === undefined) {
+      return undefined;
+    }
+
+    return getter.call(receiver);
+  }
+});

lib/6to5/transformation/templates/object-define-properties-closure.js

@@ -1,5 +0,0 @@
-
-(function (KEY) {
-  CONTENT;
-  return KEY;
-})(OBJECT);

lib/6to5/transformation/templates/object-define-properties.js

@@ -1 +0,0 @@
-Object.defineProperties(OBJECT, PROPS);

lib/6to5/transformation/transform.js

@@ -43,6 +43,7 @@ transform.moduleFormatters = {
 
 _.each({
   specNoForInOfAssignment:   require("./transformers/spec-no-for-in-of-assignment"),
+  specSetters:               require("./transformers/spec-setters"),
 
   // playground
   methodBinding:             require("./transformers/playground-method-binding"),
@@ -58,6 +59,7 @@ _.each({
   arrayComprehension:        require("./transformers/es7-array-comprehension"),
   generatorComprehension:    require("./transformers/es7-generator-comprehension"),
   arrowFunctions:            require("./transformers/es6-arrow-functions"),
+  classesFastSuper:          require("./transformers/optional-classes-fast-super"),
   classes:                   require("./transformers/es6-classes"),
 
   objectSpread:              require("./transformers/es7-object-spread"),
@@ -68,6 +70,7 @@ _.each({
   computedPropertyNames:     require("./transformers/es6-computed-property-names"),
   destructuring:             require("./transformers/es6-destructuring"),
   defaultParameters:         require("./transformers/es6-default-parameters"),
+  forOfFast:                 require("./transformers/optional-for-of-fast"),
   forOf:                     require("./transformers/es6-for-of"),
   unicodeRegex:              require("./transformers/es6-unicode-regex"),
   abstractReferences:        require("./transformers/es7-abstract-references"),

lib/6to5/transformation/transformers/es6-classes.js

@@ -3,36 +3,11 @@ var util     = require("../../util");
 var t        = require("../../types");
 
 exports.ClassDeclaration = function (node, parent, file, scope) {
-  var closure = true;
-  if (t.isProgram(parent) || t.isBlockStatement(parent)) {
-    closure = false;
-  }
-
-  var factory = new Class(node, file, scope, closure);
-  var newNode = factory.run();
-  if (factory.closure) {
-    if (closure) {
-      // declaration in an expression context...
-      // export default class Foo {}
-      scope.push({
-        kind: "var",
-        key: node.id.key,
-        id: node.id
-      });
-      return t.assignmentExpression("=", node.id, newNode);
-    } else {
-      // has a super class or PrivateDeclaration etc
-      return t.variableDeclaration("let", [
-        t.variableDeclarator(node.id, newNode)
-      ]);
-    }
-  } else {
-    return newNode;
-  }
+  return new Class(node, file, scope, true).run();
 };
 
 exports.ClassExpression = function (node, parent, file, scope) {
-  return new Class(node, file, scope, true).run();
+  return new Class(node, file, scope, false).run();
 };
 
 /**
@@ -44,11 +19,11 @@ exports.ClassExpression = function (node, parent, file, scope) {
  * @param {Boolean} closure
  */
 
-function Class(node, file, scope, closure) {
-  this.closure = closure;
-  this.scope   = scope;
-  this.node    = node;
-  this.file    = file;
+function Class(node, file, scope, isStatement) {
+  this.isStatement = isStatement;
+  this.scope       = scope;
+  this.node        = node;
+  this.file        = file;
 
   this.hasInstanceMutators = false;
   this.hasStaticMutators   = false;
@@ -83,17 +58,20 @@ Class.prototype.run = function () {
     t.variableDeclarator(className, constructor)
   ]));
 
+  var closureArgs = [];
+  var closureParams = [];
+
   //
 
   if (superName) {
-    this.closure = true;
+    closureArgs.push(superName);
 
-    // so we're only evaluating it once
-    var superRef = this.scope.generateUidBasedOnNode(superName, this.file);
-    body.unshift(t.variableDeclaration("var", [
-      t.variableDeclarator(superRef, superName)
-    ]));
-    superName = superRef;
+    if (!t.isIdentifier(superName)) {
+      var superRef = this.scope.generateUidBasedOnNode(superName, this.file);
+      superName = superRef;
+    }
+
+    closureParams.push(superName);
 
     this.superName = superName;
     body.push(t.expressionStatement(t.callExpression(file.addHelper("inherits"), [className, superName])));
@@ -103,19 +81,25 @@ Class.prototype.run = function () {
 
   t.inheritsComments(body[0], this.node);
 
-  if (this.closure) {
-    if (body.length === 1) {
-      // only a constructor so no need for a closure container
-      return constructor;
-    } else {
-      body.push(t.returnStatement(className));
-      return t.callExpression(
-        t.functionExpression(null, [], t.blockStatement(body)),
-        []
-      );
-    }
+  var init;
+
+  if (body.length === 1) {
+    // only a constructor so no need for a closure container
+    init = constructor;
   } else {
-    return body;
+    body.push(t.returnStatement(className));
+    init = t.callExpression(
+      t.functionExpression(null, closureParams, t.blockStatement(body)),
+      closureArgs
+    );
+  }
+
+  if (this.isStatement) {
+    return t.variableDeclaration("let", [
+      t.variableDeclarator(className, init)
+    ]);
+  } else {
+    return init;
   }
 };
 
@@ -149,7 +133,7 @@ Class.prototype.buildBody = function () {
 
   if (!this.hasConstructor && superName && !t.isFalsyExpression(superName)) {
     constructor.body.body.push(util.template("class-super-constructor-call", {
-      SUPER_NAME: superName
+      CLASS_NAME: className
     }, true));
   }
 
@@ -157,15 +141,11 @@ Class.prototype.buildBody = function () {
   var staticProps;
 
   if (this.hasInstanceMutators) {
-    var protoId = util.template("prototype-identifier", {
-      CLASS_NAME: className
-    });
-
-    instanceProps = util.buildDefineProperties(this.instanceMutatorMap, protoId);
+    instanceProps = util.buildDefineProperties(this.instanceMutatorMap);
   }
 
   if (this.hasStaticMutators) {
-    staticProps = util.buildDefineProperties(this.staticMutatorMap, className);
+    staticProps = util.buildDefineProperties(this.staticMutatorMap);
   }
 
   if (instanceProps || staticProps) {
@@ -190,70 +170,49 @@ Class.prototype.pushMethod = function (node) {
   var methodName = node.key;
 
   var kind = node.kind;
+  var mutatorMap = this.instanceMutatorMap;
+  if (node.static) {
+    this.hasStaticMutators = true;
+    mutatorMap = this.staticMutatorMap;
+  } else {
+    this.hasInstanceMutators = true;
+  }
 
   if (kind === "") {
-    // method
-
-    var className = this.className;
-    if (!node.static) className = t.memberExpression(className, t.identifier("prototype"));
-    methodName = t.memberExpression(className, methodName, node.computed);
-
-    var expr = t.expressionStatement(t.assignmentExpression("=", methodName, node.value));
-    t.inheritsComments(expr, node);
-    this.body.push(expr);
-  } else {
-    // mutator
-    var mutatorMap = this.instanceMutatorMap;
-    if (node.static) {
-      this.hasStaticMutators = true;
-      mutatorMap = this.staticMutatorMap;
-    } else {
-      this.hasInstanceMutators = true;
-    }
-    util.pushMutatorMap(mutatorMap, methodName, kind, node.computed, node);
+    kind = "value";
   }
+
+  util.pushMutatorMap(mutatorMap, methodName, kind, node.computed, node);
 };
 
 /**
- * Given a `methodNode`, produce a `MemberExpression` super class reference.
+ * Gets a node representing the super class value of the named property.
  *
- * @param {Node} methodNode MethodDefinition
- * @param {Node} node Identifier
- * @param {Node} parent
+ * @example
+ *
+ *   _get(Object.getPrototypeOf(CLASS.prototype), "METHOD", this)
+ *
+ * @param {Node} property
+ * @param {boolean} isStatic
+ * @param {boolean} isComputed
  *
  * @returns {Node}
  */
 
-Class.prototype.superIdentifier = function (methodNode, id, parent) {
-  var methodName = methodNode.key;
-  var superName  = this.superName || t.identifier("Function");
-
-  if (parent.property === id) {
-    return;
-  } else if (t.isCallExpression(parent, { callee: id })) {
-    // super(); -> ClassName.prototype.MethodName.call(this);
-    parent.arguments.unshift(t.thisExpression());
-
-    if (methodName.name === "constructor") {
-      // constructor() { super(); }
-      return t.memberExpression(superName, t.identifier("call"));
-    } else {
-      id = superName;
-
-      // foo() { super(); }
-      if (!methodNode.static) {
-        id = t.memberExpression(id, t.identifier("prototype"));
-      }
-
-      id = t.memberExpression(id, methodName, methodNode.computed);
-      return t.memberExpression(id, t.identifier("call"));
-    }
-  } else if (t.isMemberExpression(parent) && !methodNode.static) {
-    // super.test -> ClassName.prototype.test
-    return t.memberExpression(superName, t.identifier("prototype"));
-  } else {
-    return superName;
-  }
+Class.prototype.superProperty = function (property, isStatic, isComputed, thisExpression) {
+  return t.callExpression(
+    this.file.addHelper("get"),
+    [
+      t.callExpression(
+        t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
+        [
+          isStatic ? this.className : t.memberExpression(this.className, t.identifier("prototype"))
+        ]
+      ),
+      isComputed ? property : t.literal(property.name),
+      thisExpression
+    ]
+  );
 };
 
 /**
@@ -264,20 +223,53 @@ Class.prototype.superIdentifier = function (methodNode, id, parent) {
 
 Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
   var method = methodNode.value;
-  var self = this;
+  var self   = this;
 
   traverse(method, {
     enter: function (node, parent) {
+      var property;
+      var computed;
+      var args;
+
       if (t.isIdentifier(node, { name: "super" })) {
-        return self.superIdentifier(methodNode, node, parent);
+        if (!(t.isMemberExpression(parent) && !parent.computed && parent.property === node)) {
+          throw self.file.errorWithNode(node, "illegal use of bare super");
+        }
       } else if (t.isCallExpression(node)) {
         var callee = node.callee;
-        if (!t.isMemberExpression(callee)) return;
-        if (callee.object.name !== "super") return;
+        if (t.isIdentifier(callee, { name: "super" })) {
+          // super(); -> _get(Object.getPrototypeOf(ClassName), "MethodName", this).call(this);
+          property = methodNode.key;
+          computed = methodNode.computed;
+          args = node.arguments;
+        } else {
+          if (!t.isMemberExpression(callee)) return;
+          if (callee.object.name !== "super") return;
 
-        // super.test(); -> ClassName.prototype.MethodName.call(this);
-        t.appendToMemberExpression(callee, t.identifier("call"));
-        node.arguments.unshift(t.thisExpression());
+          // super.test(); -> _get(Object.getPrototypeOf(ClassName.prototype), "test", this).call(this);
+          property = callee.property;
+          computed = callee.computed;
+          args = node.arguments;
+        }
+      } else if (t.isMemberExpression(node)) {
+        if (!t.isIdentifier(node.object, { name: "super" })) return;
+
+        // super.name; -> _get(Object.getPrototypeOf(ClassName.prototype), "name", this);
+        property = node.property;
+        computed = node.computed;
+      }
+
+      if (property) {
+        var thisExpression = t.thisExpression();
+        var superProperty = self.superProperty(property, methodNode.static, computed, thisExpression);
+        if (args) {
+          return t.callExpression(
+            t.memberExpression(superProperty, t.identifier("call"), false),
+            [thisExpression].concat(args)
+          );
+        } else {
+          return superProperty;
+        }
       }
     }
   });
@@ -290,7 +282,7 @@ Class.prototype.replaceInstanceSuperReferences = function (methodNode) {
  */
 
 Class.prototype.pushConstructor = function (method) {
-  if (method.kind !== "") {
+  if (method.kind) {
     throw this.file.errorWithNode(method, "illegal kind for constructor method");
   }
 

lib/6to5/transformation/transformers/es6-destructuring.js

@@ -134,7 +134,7 @@ var pushPattern = function (opts) {
   var file = opts.file;
   var scope = opts.scope;
 
-  if (!t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
+  if (!t.isArrayExpression(parentId) && !t.isMemberExpression(parentId) && !t.isIdentifier(parentId)) {
     var key = scope.generateUidBasedOnNode(parentId, file);
 
     nodes.push(t.variableDeclaration("var", [

lib/6to5/transformation/transformers/es6-for-of.js

@@ -8,7 +8,7 @@ exports.ForOfStatement = function (node, parent, file, scope) {
   var stepKey   = file.generateUidIdentifier("step", scope);
   var stepValue = t.memberExpression(stepKey, t.identifier("value"));
 
-  if (t.isIdentifier(left)) {
+  if (t.isIdentifier(left) || t.isPattern(left)) {
     declar = t.expressionStatement(t.assignmentExpression("=", left, stepValue));
   } else if (t.isVariableDeclaration(left)) {
     declar = t.variableDeclaration(left.kind, [

lib/6to5/transformation/transformers/es6-generators.js

@@ -1,3 +1,9 @@
+var regenerator = require("regenerator");
+
 exports.ast = {
-  before: require("regenerator").transform
+  before: function (ast, file) {
+    regenerator.transform(ast, {
+      includeRuntime: file.opts.includeRegenerator && "if used"
+    });
+  }
 };

lib/6to5/transformation/transformers/es6-property-method-assignment.js

@@ -46,7 +46,7 @@ exports.Property = function (node, parent, file, scope) {
   }
 };
 
-exports.ObjectExpression = function (node, parent, file, scope) {
+exports.ObjectExpression = function (node) {
   var mutatorMap = {};
   var hasAny = false;
 
@@ -62,21 +62,8 @@ exports.ObjectExpression = function (node, parent, file, scope) {
 
   if (!hasAny) return;
 
-  if (node.properties.length) {
-    var objId = scope.generateUidBasedOnNode(parent, file);
-
-    return util.template("object-define-properties-closure", {
-      KEY: objId,
-      OBJECT: node,
-      CONTENT: util.template("object-define-properties", {
-        OBJECT: objId,
-        PROPS:  util.buildDefineProperties(mutatorMap)
-      })
-    });
-  } else {
-    return util.template("object-define-properties", {
-      OBJECT: node,
-      PROPS:  util.buildDefineProperties(mutatorMap)
-    });
-  }
+  return t.callExpression(
+    t.memberExpression(t.identifier("Object"), t.identifier("defineProperties")),
+    [node, util.buildDefineProperties(mutatorMap)]
+  );
 };

lib/6to5/transformation/transformers/optional-classes-fast-super.js

@@ -0,0 +1,74 @@
+var traverse = require("../../traverse");
+var util     = require("../../util");
+var t        = require("../../types");
+
+exports.optional = true;
+
+exports.Class = function (node) {
+  var superClass = node.superClass || t.identifier("Function");
+
+  var hasConstructor = false;
+  var body = node.body.body;
+
+  for (var i in body) {
+    var methodNode = body[i];
+
+    hasConstructor = hasConstructor || methodNode.key.name === "constructor";
+
+    traverse(methodNode, {
+      enter: function (node, parent) {
+        if (t.isIdentifier(node, { name: "super" })) {
+          return superIdentifier(superClass, methodNode, node, parent);
+        } else if (t.isCallExpression(node)) {
+          var callee = node.callee;
+          if (!t.isMemberExpression(callee)) return;
+          if (callee.object.name !== "super") return;
+
+          // super.test(); -> ClassName.prototype.MethodName.call(this);
+          t.appendToMemberExpression(callee, t.identifier("call"));
+          node.arguments.unshift(t.thisExpression());
+        }
+      }
+    });
+  }
+
+  if (node.superClass && !hasConstructor) {
+    body.unshift(t.methodDefinition(
+      t.identifier("constructor"),
+      util.template("class-super-constructor-call-fast", {
+        SUPER_NAME: superClass
+      })
+    ));
+  }
+};
+
+var superIdentifier = function (superClass, methodNode, id, parent) {
+  var methodName = methodNode.key;
+
+  if (parent.property === id) {
+    return;
+  } else if (t.isCallExpression(parent, { callee: id })) {
+    // super(); -> ClassName.prototype.MethodName.call(this);
+    parent.arguments.unshift(t.thisExpression());
+
+    if (methodName.name === "constructor") {
+      // constructor() { super(); }
+      return t.memberExpression(superClass, t.identifier("call"));
+    } else {
+      id = superClass;
+
+      // foo() { super(); }
+      if (!methodNode.static) {
+        id = t.memberExpression(id, t.identifier("prototype"));
+      }
+
+      id = t.memberExpression(id, methodName, methodNode.computed);
+      return t.memberExpression(id, t.identifier("call"));
+    }
+  } else if (t.isMemberExpression(parent) && !methodNode.static) {
+    // super.test -> ClassName.prototype.test
+    return t.memberExpression(superClass, t.identifier("prototype"));
+  } else {
+    return superClass;
+  }
+};

lib/6to5/transformation/transformers/optional-core-aliasing.js

@@ -31,8 +31,8 @@ exports.ast = {
             this.skip();
             return t.prependToMemberExpression(node, file._coreId);
           }
-        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && coreHas(node)) {
-          // new Promise -> new _core.Promise
+        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && node.name === "Symbol") {
+          // new Symbol -> new _core.Symbol
           return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {
           // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)

lib/6to5/transformation/transformers/optional-for-of-fast.js

@@ -0,0 +1,37 @@
+var util = require("../../util");
+var t    = require("../../types");
+
+exports.optional = true;
+
+exports.ForOfStatement = function (node, parent, file, scope) {
+  var left = node.left;
+  var declar, id;
+
+  if (t.isIdentifier(left) || t.isPattern(left)) {
+    id = left;
+  } else if (t.isVariableDeclaration(left)) {
+    id = left.declarations[0].id;
+    declar = t.variableDeclaration(left.kind, [
+      t.variableDeclarator(id)
+    ]);
+  } else {
+    throw file.errorWithNode(left, "Unknown node type " + left.type + " in ForOfStatement");
+  }
+
+  var node2 = util.template("for-of-fast", {
+    LOOP_OBJECT:  file.generateUidIdentifier("loopObject", scope),
+    IS_ARRAY:     file.generateUidIdentifier("isArray", scope),
+    OBJECT:       node.right,
+    INDEX:        file.generateUidIdentifier("i", scope),
+    ID:           id
+  });
+
+  t.inheritsComments(node2, node);
+  t.ensureBlock(node);
+
+  var block = node2.body;
+  if (declar) block.body.unshift(declar);
+  block.body = block.body.concat(node.body.body);
+
+  return node2;
+};

lib/6to5/transformation/transformers/spec-setters.js

@@ -0,0 +1,6 @@
+exports.MethodDefinition =
+exports.Property = function (node, parent, file) {
+  if (node.kind === "set" && node.value.params.length !== 1) {
+    throw file.errorWithNode(node.value, "Setters must have only one parameter");
+  }
+};

lib/6to5/traverse/index.js

@@ -4,15 +4,101 @@ var Scope = require("./scope");
 var t     = require("../types");
 var _     = require("lodash");
 
+function TraversalContext(previousContext) {
+  this.didSkip = false;
+  this.didRemove = false;
+  this.didStop = false;
+  this.didFlatten = previousContext ? previousContext.didFlatten : false;
+}
+
+TraversalContext.prototype.flatten = function () {
+  this.didFlatten = true;
+};
+
+TraversalContext.prototype.remove = function () {
+  this.didRemove = true;
+  this.skip();
+};
+
+TraversalContext.prototype.skip = function () {
+  this.didSkip = true;
+};
+
+TraversalContext.prototype.stop = function () {
+  this.didStop = true;
+  this.skip();
+};
+
+TraversalContext.prototype.maybeReplace = function (result, obj, key, node) {
+  if (result === false) return node;
+  if (result == null) return node;
+
+  var isArray = Array.isArray(result);
+
+  // inherit comments from original node to the first replacement node
+  var inheritTo = result;
+  if (isArray) inheritTo = result[0];
+  if (inheritTo) t.inheritsComments(inheritTo, node);
+
+  // replace the node
+  node = obj[key] = result;
+
+  // we're replacing a statement or block node with an array of statements so we better
+  // ensure that it's a block
+  if (isArray && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
+    t.ensureBlock(obj, key);
+  }
+
+  if (isArray) {
+    this.flatten();
+  }
+
+  return node;
+};
+
+TraversalContext.prototype.visit = function (obj, key, opts, scope, parent) {
+  var node = obj[key];
+  if (!node) return;
+
+  // type is blacklisted
+  if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) return;
+
+  var result;
+  var ourScope = scope;
+  if (t.isScope(node)) ourScope = new Scope(node, scope);
+
+  // enter
+  if (opts.enter) {
+    result = opts.enter.call(this, node, parent, ourScope);
+    node = this.maybeReplace(result, obj, key, node);
+
+    if (this.didRemove) {
+      obj[key] = null;
+      this.flatten();
+    }
+
+    // stop traversal
+    if (this.didSkip) return;
+  }
+
+  // traverse node
+  traverse(node, opts, ourScope);
+
+  // exit
+  if (opts.exit) {
+    result = opts.exit.call(this, node, parent, ourScope);
+    node = this.maybeReplace(result, obj, key, node);
+  }
+};
+
 function traverse(parent, opts, scope) {
   // falsy node
   if (!parent) return;
 
   // array of nodes
-  if (_.isArray(parent)) {
-    _.each(parent, function (node) {
-      traverse(node, opts, scope);
-    });
+  if (Array.isArray(parent)) {
+    for (var i = 0; i < parent.length; i++)
+      traverse(parent[i], opts, scope);
     return;
   }
 
@@ -21,99 +107,21 @@ function traverse(parent, opts, scope) {
   if (!keys) return;
 
   opts = opts || {};
+  var context = null;
 
-  var stopped = false;
-
-  for (var i in keys) {
-    var key = keys[i];
+  for (var j = 0; j < keys.length; j++) {
+    var key = keys[j];
     var nodes = parent[key];
     if (!nodes) continue;
 
-    var flatten = false;
-
-    var handle = function (obj, key) {
-      var node = obj[key];
-      if (!node) return;
-
-      // type is blacklisted
-      if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) return;
-
-      // replace node
-      var maybeReplace = function (result) {
-        if (result === false) return;
-        if (result == null) return;
-
-        var isArray = _.isArray(result);
-
-        // inherit comments from original node to the first replacement node
-        var inheritTo = result;
-        if (isArray) inheritTo = result[0];
-        if (inheritTo) t.inheritsComments(inheritTo, node);
-
-        // replace the node
-        node = obj[key] = result;
-
-        if (isArray) flatten = true;
-
-        // we're replacing a statement or block node with an array of statements so we better
-        // ensure that it's a block
-        if (isArray && _.contains(t.STATEMENT_OR_BLOCK_KEYS, key) && !t.isBlockStatement(obj)) {
-          t.ensureBlock(obj, key);
-        }
-      };
-
-      var skipped = false;
-      var removed = false;
-
-      var context = {
-        stop: function () {
-          skipped = stopped = true;
-        },
-
-        skip: function () {
-          skipped = true;
-        },
-
-        remove: function () {
-          this.skip();
-          removed = true;
-        }
-      };
-
-      //
-      var ourScope = scope;
-      if (t.isScope(node)) ourScope = new Scope(node, scope);
-
-      // enter
-      if (opts.enter) {
-        var result = opts.enter.call(context, node, parent, ourScope);
-        maybeReplace(result);
-
-        if (removed) {
-          obj[key] = null;
-          flatten = true;
-        }
-
-        // stop iteration
-        if (skipped) return;
+    if (Array.isArray(nodes)) {
+      for (var k = 0; k < nodes.length; k++) {
+        context = new TraversalContext(context);
+        context.visit(nodes, k, opts, scope, parent);
+        if (context.didStop) return;
       }
 
-      // traverse node
-      traverse(node, opts, ourScope);
-
-      // exit
-      if (opts.exit) {
-        maybeReplace(opts.exit.call(context, node, parent, ourScope));
-      }
-    };
-
-    if (_.isArray(nodes)) {
-      for (i in nodes) {
-        handle(nodes, i);
-        if (stopped) return;
-      }
-
-      if (flatten) {
+      if (context && context.didFlatten) {
         parent[key] = _.flatten(parent[key]);
 
         if (key === "body") {
@@ -122,8 +130,9 @@ function traverse(parent, opts, scope) {
         }
       }
     } else {
-      handle(parent, key);
-      if (stopped) return;
+      context = new TraversalContext(context);
+      context.visit(parent, key, opts, scope, parent);
+      if (context.didStop) return;
     }
   }
 }

lib/6to5/traverse/scope.js

@@ -24,7 +24,13 @@ function Scope(block, parent) {
 }
 
 var vars = require("jshint/src/vars");
-Scope.defaultDeclarations = _.flatten([vars.newEcmaIdentifiers, vars.node, vars.ecmaIdentifiers, vars.reservedVars].map(_.keys));
+
+Scope.defaultDeclarations = _.flatten([
+  vars.newEcmaIdentifiers,
+  vars.node,
+  vars.ecmaIdentifiers,
+  vars.reservedVars
+].map(_.keys));
 
 Scope.add = function (node, references) {
   if (!node) return;

lib/6to5/types/builder-keys.json

@@ -16,6 +16,7 @@
   "Literal":                 ["value"],
   "LogicalExpression":       ["operator", "left", "right"],
   "MemberExpression":        ["object", "property", "computed"],
+  "MethodDefinition":        ["key", "value", "computed", "kind"],
   "NewExpression":           ["callee", "arguments"],
   "ObjectExpression":        ["properties"],
   "Program":                 ["body"],

lib/6to5/types/index.js

@@ -320,7 +320,11 @@ t.toBlock = function (node, parent) {
     return node;
   }
 
-  if (!_.isArray(node)) {
+  if (t.isEmptyStatement(node)) {
+    node = [];
+  }
+
+  if (!Array.isArray(node)) {
     if (!t.isStatement(node)) {
       if (t.isFunction(parent)) {
         node = t.returnStatement(node);

lib/6to5/util.js

@@ -39,7 +39,7 @@ exports.list = function (val) {
 
 exports.regexify = function (val) {
   if (!val) return new RegExp(/.^/);
-  if (_.isArray(val)) val = val.join("|");
+  if (Array.isArray(val)) val = val.join("|");
   if (_.isString(val)) return new RegExp(val);
   if (_.isRegExp(val)) return val;
   throw new TypeError("illegal type for regexify");
@@ -48,7 +48,7 @@ exports.regexify = function (val) {
 exports.arrayify = function (val) {
   if (!val) return [];
   if (_.isString(val)) return exports.list(val);
-  if (_.isArray(val)) return val;
+  if (Array.isArray(val)) return val;
   throw new TypeError("illegal type for arrayify");
 };
 
@@ -101,7 +101,12 @@ exports.buildDefineProperties = function (mutatorMap) {
 
     var propNode = t.property("init", map._key, mapNode, map._computed);
 
+    if (!map.get && !map.set) {
+      map.writable = t.literal(true);
+    }
+
     map.enumerable = t.literal(true);
+    map.configurable = t.literal(true);
 
     _.each(map, function (node, key) {
       if (key[0] === "_") return;
@@ -188,7 +193,13 @@ exports.codeFrame = function (lines, lineNumber, colNumber) {
 
 exports.repeat = function (width, cha) {
   cha = cha || " ";
-  return new Array(width + 1).join(cha);
+
+  var result = "";
+  for (var i = 0; i < width; i++) {
+    result += cha;
+  }
+
+  return result;
 };
 
 exports.normaliseAst = function (ast, comments, tokens) {

package.json

@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into readable vanilla ES5 with source maps",
-  "version": "2.8.2",
+  "version": "2.10.1",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/6to5/6to5",
   "repository": {
@@ -39,11 +39,11 @@
     "test": "make test"
   },
   "dependencies": {
-    "acorn-6to5": "0.11.1-11",
+    "acorn-6to5": "0.11.1-13",
     "ast-types": "~0.6.1",
     "chokidar": "0.11.1",
     "commander": "2.5.0",
-    "core-js": "^0.4.1",
+    "core-js": "^0.4.4",
     "estraverse": "1.8.0",
     "esutils": "1.1.6",
     "esvalid": "^1.1.0",

test/browserify.js

@@ -12,7 +12,7 @@ suite("browserify", function() {
       assert.ok(bundle.length, "bundle output code");
 
       // ensure that the code runs without throwing an exception
-      vm.runInNewContext(bundle, {});
+      vm.runInNewContext("var global = this;\n" + bundle, {});
       done();
     })
   })

test/esnext.js

@@ -1,5 +1,3 @@
-if (!process.env.ALL_6TO5_TESTS) return;
-
 require("./_transformation-helper")({
   name: "esnext"
 });

test/fixtures/esnext/es6-classes/getter-setter-super.js

@@ -1,9 +1,11 @@
-class Animal {
+class Base {
   get sound() {
     return 'I am a ' + this.type + '.';
   }
 }
 
+class Animal extends Base {}
+
 class Cat extends Animal {
   get type() { return 'cat'; }
 

test/fixtures/generation/types/UpdateExpression/actual.js

@@ -1,2 +1,3 @@
 ++i;
 i++;
+(foo++).test();

test/fixtures/generation/types/UpdateExpression/expected.js

@@ -1,2 +1,3 @@
 ++i;
 i++;
+(foo++).test();

test/fixtures/transformation/es6-classes/accessing-super-class/actual.js

@@ -3,7 +3,6 @@ class Test extends Foo {
     woops.super.test();
     super();
     super.test();
-    foob(super);
 
     super(...arguments);
     super("test", ...arguments);

test/fixtures/transformation/es6-classes/accessing-super-class/expected.js

@@ -1,6 +1,33 @@
 "use strict";
 
 var _slice = Array.prototype.slice;
+var _prototypeProperties = function (child, staticProps, instanceProps) {
+  if (staticProps) Object.defineProperties(child, staticProps);
+  if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
+};
+
+var _get = function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent, property, receiver);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+    if (getter === undefined) {
+      return undefined;
+    }
+    return getter.call(receiver);
+  }
+};
+
 var _inherits = function (child, parent) {
   if (typeof parent !== "function" && parent !== null) {
     throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
@@ -16,37 +43,47 @@ var _inherits = function (child, parent) {
   if (parent) child.__proto__ = parent;
 };
 
-var Test = (function () {
-  var _Foo = Foo;
+var Test = (function (Foo) {
   var Test = function Test() {
-    var _Foo$prototype$test, _Foo$prototype$test2;
+    var _get2, _get3, _get4, _get5;
     woops["super"].test();
-    _Foo.call(this);
-    _Foo.prototype.test.call(this);
-    foob(_Foo);
+    _get(Object.getPrototypeOf(Test.prototype), "constructor", this).call(this);
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
 
-    _Foo.call.apply(_Foo, [this].concat(_slice.call(arguments)));
-    _Foo.call.apply(_Foo, [this, "test"].concat(_slice.call(arguments)));
+    (_get2 = _get(Object.getPrototypeOf(Test.prototype), "constructor", this)).call.apply(_get2, [this].concat(_slice.call(arguments)));
+    (_get3 = _get(Object.getPrototypeOf(Test.prototype), "constructor", this)).call.apply(_get3, [this, "test"].concat(_slice.call(arguments)));
 
-    (_Foo$prototype$test = _Foo.prototype.test).call.apply(_Foo$prototype$test, [this].concat(_slice.call(arguments)));
-    (_Foo$prototype$test2 = _Foo.prototype.test).call.apply(_Foo$prototype$test2, [this, "test"].concat(_slice.call(arguments)));
+    (_get4 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get4, [this].concat(_slice.call(arguments)));
+    (_get5 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get5, [this, "test"].concat(_slice.call(arguments)));
   };
 
-  _inherits(Test, _Foo);
+  _inherits(Test, Foo);
 
-  Test.prototype.test = function () {
-    var _Foo$prototype$test3, _Foo$prototype$test4;
-    _Foo.prototype.test.call(this);
-    (_Foo$prototype$test3 = _Foo.prototype.test).call.apply(_Foo$prototype$test3, [this].concat(_slice.call(arguments)));
-    (_Foo$prototype$test4 = _Foo.prototype.test).call.apply(_Foo$prototype$test4, [this, "test"].concat(_slice.call(arguments)));
-  };
-
-  Test.foo = function () {
-    var _Foo$foo, _Foo$foo2;
-    _Foo.foo.call(this);
-    (_Foo$foo = _Foo.foo).call.apply(_Foo$foo, [this].concat(_slice.call(arguments)));
-    (_Foo$foo2 = _Foo.foo).call.apply(_Foo$foo2, [this, "test"].concat(_slice.call(arguments)));
-  };
+  _prototypeProperties(Test, {
+    foo: {
+      value: function () {
+        var _get6, _get7;
+        _get(Object.getPrototypeOf(Test), "foo", this).call(this);
+        (_get6 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get6, [this].concat(_slice.call(arguments)));
+        (_get7 = _get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_get7, [this, "test"].concat(_slice.call(arguments)));
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  }, {
+    test: {
+      value: function () {
+        var _get8, _get9;
+        _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
+        (_get8 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get8, [this].concat(_slice.call(arguments)));
+        (_get9 = _get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_get9, [this, "test"].concat(_slice.call(arguments)));
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  });
 
   return Test;
-})();
+})(Foo);

test/fixtures/transformation/es6-classes/accessing-super-properties/expected.js

@@ -1,5 +1,27 @@
 "use strict";
 
+var _get = function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent, property, receiver);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+    if (getter === undefined) {
+      return undefined;
+    }
+    return getter.call(receiver);
+  }
+};
+
 var _inherits = function (child, parent) {
   if (typeof parent !== "function" && parent !== null) {
     throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
@@ -15,14 +37,13 @@ var _inherits = function (child, parent) {
   if (parent) child.__proto__ = parent;
 };
 
-var Test = (function () {
-  var _Foo = Foo;
+var Test = (function (Foo) {
   var Test = function Test() {
-    _Foo.prototype.test;
-    _Foo.prototype.test.whatever;
+    _get(Object.getPrototypeOf(Test.prototype), "test", this);
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever;
   };
 
-  _inherits(Test, _Foo);
+  _inherits(Test, Foo);
 
   return Test;
-})();
+})(Foo);

test/fixtures/transformation/es6-classes/bare-super/actual.js

@@ -0,0 +1,5 @@
+class Test {
+  constructor() {
+    console.log(super);
+  }
+}

test/fixtures/transformation/es6-classes/bare-super/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "illegal use of bare super"
+}

test/fixtures/transformation/es6-classes/calling-super-properties/expected.js

@@ -1,5 +1,32 @@
 "use strict";
 
+var _prototypeProperties = function (child, staticProps, instanceProps) {
+  if (staticProps) Object.defineProperties(child, staticProps);
+  if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
+};
+
+var _get = function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent, property, receiver);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+    if (getter === undefined) {
+      return undefined;
+    }
+    return getter.call(receiver);
+  }
+};
+
 var _inherits = function (child, parent) {
   if (typeof parent !== "function" && parent !== null) {
     throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
@@ -15,18 +42,24 @@ var _inherits = function (child, parent) {
   if (parent) child.__proto__ = parent;
 };
 
-var Test = (function () {
-  var _Foo = Foo;
+var Test = (function (Foo) {
   var Test = function Test() {
-    _Foo.prototype.test.whatever();
-    _Foo.prototype.test.call(this);
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).whatever();
+    _get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
   };
 
-  _inherits(Test, _Foo);
+  _inherits(Test, Foo);
 
-  Test.test = function () {
-    return _Foo.wow.call(this);
-  };
+  _prototypeProperties(Test, {
+    test: {
+      value: function () {
+        return _get(Object.getPrototypeOf(Test), "wow", this).call(this);
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  });
 
   return Test;
-})();
+})(Foo);

test/fixtures/transformation/es6-classes/constructor/expected.js

@@ -19,13 +19,12 @@ var Test = function Test() {
   this.state = "test";
 };
 
-var Foo = (function () {
-  var _Bar = Bar;
+var Foo = (function (Bar) {
   var Foo = function Foo() {
     this.state = "test";
   };
 
-  _inherits(Foo, _Bar);
+  _inherits(Foo, Bar);
 
   return Foo;
-})();
+})(Bar);

test/fixtures/transformation/es6-classes/instance-getter-and-setter/expected.js

@@ -5,16 +5,21 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  test: {
-    get: function () {
-      return 5 + 5;
-    },
-    set: function (val) {
-      this._test = val;
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    test: {
+      get: function () {
+        return 5 + 5;
+      },
+      set: function (val) {
+        this._test = val;
+      },
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/instance-getter/expected.js

@@ -5,13 +5,18 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  test: {
-    get: function () {
-      return 5 + 5;
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    test: {
+      get: function () {
+        return 5 + 5;
+      },
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/instance-method/expected.js

@@ -1,7 +1,23 @@
 "use strict";
 
-var Test = function Test() {};
-
-Test.prototype.test = function () {
-  return 5 + 5;
+var _prototypeProperties = function (child, staticProps, instanceProps) {
+  if (staticProps) Object.defineProperties(child, staticProps);
+  if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
+
+var Test = (function () {
+  var Test = function Test() {};
+
+  _prototypeProperties(Test, null, {
+    test: {
+      value: function () {
+        return 5 + 5;
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/instance-setter/expected.js

@@ -5,13 +5,18 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  test: {
-    set: function (val) {
-      this._test = val;
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    test: {
+      set: function (val) {
+        this._test = val;
+      },
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})();

test/fixtures/transformation/es6-classes/statement/expected.js

@@ -1,5 +1,10 @@
 "use strict";
 
+var _prototypeProperties = function (child, staticProps, instanceProps) {
+  if (staticProps) Object.defineProperties(child, staticProps);
+  if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
+};
+
 var BaseView = function BaseView() {
   this.autoRender = true;
 };
@@ -11,9 +16,16 @@ var BaseView = function () {
 var BaseView = (function () {
   var _class2 = function () {};
 
-  _class2.prototype.foo = function () {
-    this.autoRender = true;
-  };
+  _prototypeProperties(_class2, null, {
+    foo: {
+      value: function () {
+        this.autoRender = true;
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  });
 
   return _class2;
 })();

test/fixtures/transformation/es6-classes/static/expected.js

@@ -5,14 +5,23 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var A = function A() {};
+var A = (function () {
+  var A = function A() {};
 
-A.a = function () {};
+  _prototypeProperties(A, {
+    a: {
+      value: function () {},
+      writable: true,
+      enumerable: true,
+      configurable: true
+    },
+    b: {
+      get: function () {},
+      set: function (b) {},
+      enumerable: true,
+      configurable: true
+    }
+  });
 
-_prototypeProperties(A, {
-  b: {
-    get: function () {},
-    set: function (b) {},
-    enumerable: true
-  }
-});
+  return A;
+})();

test/fixtures/transformation/es6-classes/super-class-id-member-expression/expected.js

@@ -15,28 +15,26 @@ var _inherits = function (child, parent) {
   if (parent) child.__proto__ = parent;
 };
 
-var BaseController = (function () {
-  var _Chaplin$Controller = Chaplin.Controller;
+var BaseController = (function (_Chaplin$Controller) {
   var BaseController = function BaseController() {
-    if (_Chaplin$Controller !== null) {
-      _Chaplin$Controller.apply(this, arguments);
+    if (Object.getPrototypeOf(BaseController) !== null) {
+      Object.getPrototypeOf(BaseController).apply(this, arguments);
     }
   };
 
   _inherits(BaseController, _Chaplin$Controller);
 
   return BaseController;
-})();
+})(Chaplin.Controller);
 
-var BaseController2 = (function () {
-  var _Chaplin$Controller$Another = Chaplin.Controller.Another;
+var BaseController2 = (function (_Chaplin$Controller$Another) {
   var BaseController2 = function BaseController2() {
-    if (_Chaplin$Controller$Another !== null) {
-      _Chaplin$Controller$Another.apply(this, arguments);
+    if (Object.getPrototypeOf(BaseController2) !== null) {
+      Object.getPrototypeOf(BaseController2).apply(this, arguments);
     }
   };
 
   _inherits(BaseController2, _Chaplin$Controller$Another);
 
   return BaseController2;
-})();
+})(Chaplin.Controller.Another);

test/fixtures/transformation/es6-classes/super-class/expected.js

@@ -15,15 +15,14 @@ var _inherits = function (child, parent) {
   if (parent) child.__proto__ = parent;
 };
 
-var Test = (function () {
-  var _Foo = Foo;
+var Test = (function (Foo) {
   var Test = function Test() {
-    if (_Foo !== null) {
-      _Foo.apply(this, arguments);
+    if (Object.getPrototypeOf(Test) !== null) {
+      Object.getPrototypeOf(Test).apply(this, arguments);
     }
   };
 
-  _inherits(Test, _Foo);
+  _inherits(Test, Foo);
 
   return Test;
-})();
+})(Foo);

test/fixtures/transformation/es6-classes/super-function-fallback/expected.js

@@ -1,5 +1,28 @@
 "use strict";
 
-var Test = function Test() {
-  Function.prototype.hasOwnProperty.call(this, "test");
+var _get = function get(object, property, receiver) {
+  var desc = Object.getOwnPropertyDescriptor(object, property);
+
+  if (desc === undefined) {
+    var parent = Object.getPrototypeOf(object);
+
+    if (parent === null) {
+      return undefined;
+    } else {
+      return get(parent, property, receiver);
+    }
+  } else if ("value" in desc && desc.writable) {
+    return desc.value;
+  } else {
+    var getter = desc.get;
+    if (getter === undefined) {
+      return undefined;
+    }
+    return getter.call(receiver);
+  }
 };
+
+var Test = function Test() {
+  _get(Object.getPrototypeOf(Test.prototype), "hasOwnProperty", this).call(this, "test");
+};
+

test/fixtures/transformation/es6-constants/destructuring/expected.js

@@ -1,38 +1,18 @@
 "use strict";
 
-var _slicedToArray = function (arr, i) {
-  if (Array.isArray(arr)) {
-    return arr;
-  } else {
-    var _arr = [];
-
-    for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
-      _arr.push(_step.value);
-
-      if (i && _arr.length === i) break;
-    }
-
-    return _arr;
-  }
-};
-
 var _ref = [1, 2];
 
-var _ref2 = _slicedToArray(_ref, 2);
+var a = _ref[0];
+var b = _ref[1];
+var _ref2 = [3, 4];
 
-var a = _ref2[0];
-var b = _ref2[1];
-var _ref3 = [3, 4];
+var c = _ref2[0];
+var d = _ref2[1];
+var _ref3 = { e: 5, f: 6 };
 
-var _ref3 = _slicedToArray(_ref3, 2);
+var e = _ref3.e;
+var f = _ref3.f;
+var _ref4 = { a: 7, b: 8 };
 
-var c = _ref3[0];
-var d = _ref3[1];
-var _ref4 = { e: 5, f: 6 };
-
-var e = _ref4.e;
-var f = _ref4.f;
-var _ref5 = { a: 7, b: 8 };
-
-var g = _ref5.a;
-var h = _ref5.b;
+var g = _ref4.a;
+var h = _ref4.b;

test/fixtures/transformation/es6-destructuring/array/expected.js

@@ -18,13 +18,11 @@ var _slicedToArray = function (arr, i) {
 
 var _ref = ["hello", [", ", "junk"], ["world"]];
 
-var _ref2 = _slicedToArray(_ref, 4);
+var a = _ref[0];
+var _ref$1 = _slicedToArray(_ref[1], 1);
 
-var a = _ref2[0];
-var _ref2$1 = _slicedToArray(_ref2[1], 1);
+var b = _ref$1[0];
+var _ref$2 = _slicedToArray(_ref[2], 1);
 
-var b = _ref2$1[0];
-var _ref2$2 = _slicedToArray(_ref2[2], 1);
-
-var c = _ref2$2[0];
-var d = _ref2[3];
+var c = _ref$2[0];
+var d = _ref[3];

test/fixtures/transformation/es6-destructuring/empty/expected.js

@@ -18,13 +18,11 @@ var _slicedToArray = function (arr, i) {
 
 var _ref = ["foo", "hello", [", ", "junk"], ["world"]];
 
-var _ref2 = _slicedToArray(_ref, 5);
+var a = _ref[1];
+var _ref$2 = _slicedToArray(_ref[2], 1);
 
-var a = _ref2[1];
-var _ref2$2 = _slicedToArray(_ref2[2], 1);
+var b = _ref$2[0];
+var _ref$3 = _slicedToArray(_ref[3], 1);
 
-var b = _ref2$2[0];
-var _ref2$3 = _slicedToArray(_ref2[3], 1);
-
-var c = _ref2$3[0];
-var d = _ref2[4];
+var c = _ref$3[0];
+var d = _ref[4];

test/fixtures/transformation/es6-modules-amd-strict/exports-from/expected.js

@@ -7,15 +7,17 @@ define(["exports", "foo"], function (exports, _foo) {
     };
   };
 
-  var _exportsWildcard = function (obj) {
-    for (var i in obj) {
-      if (exports[i] !== undefined) {
-        exports[i] = obj[i];
+  var _defaults = function (obj, defaults) {
+    for (var key in defaults) {
+      if (obj[key] === undefined) {
+        obj[key] = defaults[key];
       }
     }
+
+    return obj;
   };
 
-  _exportsWildcard(_interopRequireWildcard(_foo));
+  _defaults(exports, _interopRequireWildcard(_foo));
 
   exports.foo = _foo.foo;
   exports.foo = _foo.foo;

test/fixtures/transformation/es6-modules-amd/exports-from/expected.js

@@ -7,15 +7,17 @@ define(["exports", "foo"], function (exports, _foo) {
     };
   };
 
-  var _exportsWildcard = function (obj) {
-    for (var i in obj) {
-      if (exports[i] !== undefined) {
-        exports[i] = obj[i];
+  var _defaults = function (obj, defaults) {
+    for (var key in defaults) {
+      if (obj[key] === undefined) {
+        obj[key] = defaults[key];
       }
     }
+
+    return obj;
   };
 
-  _exportsWildcard(_interopRequireWildcard(_foo));
+  _defaults(exports, _interopRequireWildcard(_foo));
 
   exports.foo = _foo.foo;
   exports.foo = _foo.foo;

test/fixtures/transformation/es6-modules-common-strict/exports-from/expected.js

@@ -6,15 +6,17 @@ var _interopRequireWildcard = function (obj) {
   };
 };
 
-var _exportsWildcard = function (obj) {
-  for (var i in obj) {
-    if (exports[i] !== undefined) {
-      exports[i] = obj[i];
+var _defaults = function (obj, defaults) {
+  for (var key in defaults) {
+    if (obj[key] === undefined) {
+      obj[key] = defaults[key];
     }
   }
+
+  return obj;
 };
 
-_exportsWildcard(_interopRequireWildcard(require("foo")));
+_defaults(exports, _interopRequireWildcard(require("foo")));
 
 exports.foo = require("foo").foo;
 exports.foo = require("foo").foo;

test/fixtures/transformation/es6-modules-common/exports-from/expected.js

@@ -6,15 +6,17 @@ var _interopRequireWildcard = function (obj) {
   };
 };
 
-var _exportsWildcard = function (obj) {
-  for (var i in obj) {
-    if (exports[i] !== undefined) {
-      exports[i] = obj[i];
+var _defaults = function (obj, defaults) {
+  for (var key in defaults) {
+    if (obj[key] === undefined) {
+      obj[key] = defaults[key];
     }
   }
+
+  return obj;
 };
 
-_exportsWildcard(_interopRequireWildcard(require("foo")));
+_defaults(exports, _interopRequireWildcard(require("foo")));
 
 exports.foo = require("foo").foo;
 exports.foo = require("foo").foo;

test/fixtures/transformation/es6-modules-umd-strict/exports-from/expected.js

@@ -13,15 +13,17 @@
     };
   };
 
-  var _exportsWildcard = function (obj) {
-    for (var i in obj) {
-      if (exports[i] !== undefined) {
-        exports[i] = obj[i];
+  var _defaults = function (obj, defaults) {
+    for (var key in defaults) {
+      if (obj[key] === undefined) {
+        obj[key] = defaults[key];
       }
     }
+
+    return obj;
   };
 
-  _exportsWildcard(_interopRequireWildcard(_foo));
+  _defaults(exports, _interopRequireWildcard(_foo));
 
   exports.foo = _foo.foo;
   exports.foo = _foo.foo;

test/fixtures/transformation/es6-modules-umd/exports-from/expected.js

@@ -13,15 +13,17 @@
     };
   };
 
-  var _exportsWildcard = function (obj) {
-    for (var i in obj) {
-      if (exports[i] !== undefined) {
-        exports[i] = obj[i];
+  var _defaults = function (obj, defaults) {
+    for (var key in defaults) {
+      if (obj[key] === undefined) {
+        obj[key] = defaults[key];
       }
     }
+
+    return obj;
   };
 
-  _exportsWildcard(_interopRequireWildcard(_foo));
+  _defaults(exports, _interopRequireWildcard(_foo));
 
   exports.foo = _foo.foo;
   exports.foo = _foo.foo;

test/fixtures/transformation/es6-property-method-assignment/computed/expected.js

@@ -18,7 +18,8 @@ var obj = Object.defineProperties({}, _defineProperty({}, x, {
   set: function (value) {
     valueSet = value;
   },
-  enumerable: true
+  enumerable: true,
+  configurable: true
 }));
 obj.y = "foo";
 obj.y === 1 && valueSet === "foo";

test/fixtures/transformation/es6-property-method-assignment/getter-and-setter/expected.js

@@ -8,6 +8,7 @@ var obj = Object.defineProperties({}, {
     set: function (value) {
       this._foo = value;
     },
-    enumerable: true
+    enumerable: true,
+    configurable: true
   }
 });

test/fixtures/transformation/es6-property-method-assignment/getter/expected.js

@@ -5,6 +5,7 @@ var obj = Object.defineProperties({}, {
     get: function () {
       return 5 + 5;
     },
-    enumerable: true
+    enumerable: true,
+    configurable: true
   }
 });

test/fixtures/transformation/es6-property-method-assignment/setter/expected.js

@@ -5,6 +5,7 @@ var obj = Object.defineProperties({}, {
     set: function (value) {
       this._foo = value;
     },
-    enumerable: true
+    enumerable: true,
+    configurable: true
   }
 });

test/fixtures/transformation/optional-classes-fast-super/accessing-super-class/actual.js

@@ -0,0 +1,25 @@
+class Test extends Foo {
+  constructor() {
+    woops.super.test();
+    super();
+    super.test();
+
+    super(...arguments);
+    super("test", ...arguments);
+
+    super.test(...arguments);
+    super.test("test", ...arguments);
+  }
+
+  test() {
+    super();
+    super(...arguments);
+    super("test", ...arguments);
+  }
+
+  static foo() {
+    super();
+    super(...arguments);
+    super("test", ...arguments);
+  }
+}

test/fixtures/transformation/optional-classes-fast-super/accessing-super-class/expected.js

@@ -0,0 +1,67 @@
+"use strict";
+
+var _slice = Array.prototype.slice;
+var _prototypeProperties = function (child, staticProps, instanceProps) {
+  if (staticProps) Object.defineProperties(child, staticProps);
+  if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
+};
+
+var _inherits = function (child, parent) {
+  if (typeof parent !== "function" && parent !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+  }
+  child.prototype = Object.create(parent && parent.prototype, {
+    constructor: {
+      value: child,
+      enumerable: false,
+      writable: true,
+      configurable: true
+    }
+  });
+  if (parent) child.__proto__ = parent;
+};
+
+var Test = (function (Foo) {
+  var Test = function Test() {
+    var _Foo$prototype$test, _Foo$prototype$test2;
+    woops["super"].test();
+    Foo.call(this);
+    Foo.prototype.test.call(this);
+
+    Foo.call.apply(Foo, [this].concat(_slice.call(arguments)));
+    Foo.call.apply(Foo, [this, "test"].concat(_slice.call(arguments)));
+
+    (_Foo$prototype$test = Foo.prototype.test).call.apply(_Foo$prototype$test, [this].concat(_slice.call(arguments)));
+    (_Foo$prototype$test2 = Foo.prototype.test).call.apply(_Foo$prototype$test2, [this, "test"].concat(_slice.call(arguments)));
+  };
+
+  _inherits(Test, Foo);
+
+  _prototypeProperties(Test, {
+    foo: {
+      value: function () {
+        var _Foo$foo, _Foo$foo2;
+        Foo.foo.call(this);
+        (_Foo$foo = Foo.foo).call.apply(_Foo$foo, [this].concat(_slice.call(arguments)));
+        (_Foo$foo2 = Foo.foo).call.apply(_Foo$foo2, [this, "test"].concat(_slice.call(arguments)));
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  }, {
+    test: {
+      value: function () {
+        var _Foo$prototype$test3, _Foo$prototype$test4;
+        Foo.prototype.test.call(this);
+        (_Foo$prototype$test3 = Foo.prototype.test).call.apply(_Foo$prototype$test3, [this].concat(_slice.call(arguments)));
+        (_Foo$prototype$test4 = Foo.prototype.test).call.apply(_Foo$prototype$test4, [this, "test"].concat(_slice.call(arguments)));
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})(Foo);

test/fixtures/transformation/optional-classes-fast-super/accessing-super-properties/actual.js

@@ -0,0 +1,6 @@
+class Test extends Foo {
+  constructor() {
+    super.test;
+    super.test.whatever;
+  }
+}

test/fixtures/transformation/optional-classes-fast-super/accessing-super-properties/expected.js

@@ -0,0 +1,27 @@
+"use strict";
+
+var _inherits = function (child, parent) {
+  if (typeof parent !== "function" && parent !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+  }
+  child.prototype = Object.create(parent && parent.prototype, {
+    constructor: {
+      value: child,
+      enumerable: false,
+      writable: true,
+      configurable: true
+    }
+  });
+  if (parent) child.__proto__ = parent;
+};
+
+var Test = (function (Foo) {
+  var Test = function Test() {
+    Foo.prototype.test;
+    Foo.prototype.test.whatever;
+  };
+
+  _inherits(Test, Foo);
+
+  return Test;
+})(Foo);

test/fixtures/transformation/optional-classes-fast-super/calling-super-properties/actual.js

@@ -0,0 +1,10 @@
+class Test extends Foo {
+  constructor() {
+    super.test.whatever();
+    super.test();
+  }
+
+  static test() {
+    return super.wow();
+  }
+}

test/fixtures/transformation/optional-classes-fast-super/calling-super-properties/expected.js

@@ -0,0 +1,43 @@
+"use strict";
+
+var _prototypeProperties = function (child, staticProps, instanceProps) {
+  if (staticProps) Object.defineProperties(child, staticProps);
+  if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
+};
+
+var _inherits = function (child, parent) {
+  if (typeof parent !== "function" && parent !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+  }
+  child.prototype = Object.create(parent && parent.prototype, {
+    constructor: {
+      value: child,
+      enumerable: false,
+      writable: true,
+      configurable: true
+    }
+  });
+  if (parent) child.__proto__ = parent;
+};
+
+var Test = (function (Foo) {
+  var Test = function Test() {
+    Foo.prototype.test.whatever();
+    Foo.prototype.test.call(this);
+  };
+
+  _inherits(Test, Foo);
+
+  _prototypeProperties(Test, {
+    test: {
+      value: function () {
+        return Foo.wow.call(this);
+      },
+      writable: true,
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})(Foo);

test/fixtures/transformation/optional-classes-fast-super/options.json

@@ -0,0 +1,3 @@
+{
+  "optional": ["classesFastSuper"]
+}

test/fixtures/transformation/optional-classes-fast-super/super-class-id-member-expression/actual.js

@@ -0,0 +1,7 @@
+class BaseController extends Chaplin.Controller {
+
+}
+
+class BaseController2 extends Chaplin.Controller.Another {
+
+}

test/fixtures/transformation/optional-classes-fast-super/super-class-id-member-expression/expected.js

@@ -0,0 +1,40 @@
+"use strict";
+
+var _inherits = function (child, parent) {
+  if (typeof parent !== "function" && parent !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+  }
+  child.prototype = Object.create(parent && parent.prototype, {
+    constructor: {
+      value: child,
+      enumerable: false,
+      writable: true,
+      configurable: true
+    }
+  });
+  if (parent) child.__proto__ = parent;
+};
+
+var BaseController = (function (_Chaplin$Controller) {
+  var BaseController = function BaseController() {
+    if (Chaplin.Controller != null) {
+      Chaplin.Controller.apply(this, arguments);
+    }
+  };
+
+  _inherits(BaseController, _Chaplin$Controller);
+
+  return BaseController;
+})(Chaplin.Controller);
+
+var BaseController2 = (function (_Chaplin$Controller$Another) {
+  var BaseController2 = function BaseController2() {
+    if (Chaplin.Controller.Another != null) {
+      Chaplin.Controller.Another.apply(this, arguments);
+    }
+  };
+
+  _inherits(BaseController2, _Chaplin$Controller$Another);
+
+  return BaseController2;
+})(Chaplin.Controller.Another);

test/fixtures/transformation/optional-classes-fast-super/super-class/actual.js

@@ -0,0 +1 @@
+class Test extends Foo { }

test/fixtures/transformation/optional-classes-fast-super/super-class/expected.js

@@ -0,0 +1,28 @@
+"use strict";
+
+var _inherits = function (child, parent) {
+  if (typeof parent !== "function" && parent !== null) {
+    throw new TypeError("Super expression must either be null or a function, not " + typeof parent);
+  }
+  child.prototype = Object.create(parent && parent.prototype, {
+    constructor: {
+      value: child,
+      enumerable: false,
+      writable: true,
+      configurable: true
+    }
+  });
+  if (parent) child.__proto__ = parent;
+};
+
+var Test = (function (Foo) {
+  var Test = function Test() {
+    if (Foo != null) {
+      Foo.apply(this, arguments);
+    }
+  };
+
+  _inherits(Test, Foo);
+
+  return Test;
+})(Foo);

test/fixtures/transformation/optional-classes-fast-super/super-function-fallback/actual.js

@@ -0,0 +1,5 @@
+class Test {
+  constructor() {
+    super.hasOwnProperty("test");
+  }
+}

test/fixtures/transformation/optional-classes-fast-super/super-function-fallback/expected.js

@@ -0,0 +1,5 @@
+"use strict";
+
+var Test = function Test() {
+  Function.prototype.hasOwnProperty.call(this, "test");
+};

test/fixtures/transformation/optional-core-aliasing/es6-destructuring/expected.js

@@ -24,13 +24,11 @@ var _core = _interopRequire(require("core-js/library"));
 
 var _ref = ["hello", [", ", "junk"], ["world"]];
 
-var _ref2 = _slicedToArray(_ref, 4);
+var a = _ref[0];
+var _ref$1 = _slicedToArray(_ref[1], 1);
 
-var a = _ref2[0];
-var _ref2$1 = _slicedToArray(_ref2[1], 1);
+var b = _ref$1[0];
+var _ref$2 = _slicedToArray(_ref[2], 1);
 
-var b = _ref2$1[0];
-var _ref2$2 = _slicedToArray(_ref2[2], 1);
-
-var c = _ref2$2[0];
-var d = _ref2[3];
+var c = _ref$2[0];
+var d = _ref[3];

test/fixtures/transformation/optional-core-aliasing/ignore-natives/actual.js

@@ -0,0 +1 @@
+obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/ignore-natives/expected.js

@@ -0,0 +1,9 @@
+"use strict";
+
+var _interopRequire = function (obj) {
+  return obj && (obj["default"] || obj);
+};
+
+var _core = _interopRequire(require("core-js/library"));
+
+obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/map-symbol/actual.js

@@ -0,0 +1,2 @@
+Symbol("test");
+Symbol();

test/fixtures/transformation/optional-core-aliasing/map-symbol/expected.js

@@ -0,0 +1,10 @@
+"use strict";
+
+var _interopRequire = function (obj) {
+  return obj && (obj["default"] || obj);
+};
+
+var _core = _interopRequire(require("core-js/library"));
+
+_core.Symbol("test");
+_core.Symbol();

test/fixtures/transformation/optional-proto-to-assign/class/expected.js

@@ -25,15 +25,14 @@ var _inherits = function (child, parent) {
   if (parent) _defaults(child, parent);
 };
 
-var Foo = (function () {
-  var _Bar = Bar;
+var Foo = (function (Bar) {
   var Foo = function Foo() {
-    if (_Bar !== null) {
-      _Bar.apply(this, arguments);
+    if (Object.getPrototypeOf(Foo) !== null) {
+      Object.getPrototypeOf(Foo).apply(this, arguments);
     }
   };
 
-  _inherits(Foo, _Bar);
+  _inherits(Foo, Bar);
 
   return Foo;
-})();
+})(Bar);

test/fixtures/transformation/playground/object-getter-memoization/expected.js

@@ -14,32 +14,40 @@ var _defineProperty = function (obj, key, value) {
   });
 };
 
-var Foo = function Foo() {};
+var Foo = (function () {
+  var Foo = function Foo() {};
 
-_prototypeProperties(Foo, null, _defineProperty({
-  bar: {
+  _prototypeProperties(Foo, null, _defineProperty({
+    bar: {
+      get: function () {
+        return _defineProperty(this, "bar", complex()).bar;
+      },
+      enumerable: true,
+      configurable: true
+    }
+  }, bar, {
     get: function () {
-      return _defineProperty(this, "bar", complex()).bar;
+      return _defineProperty(this, bar, complex())[bar];
     },
-    enumerable: true
-  }
-}, bar, {
-  get: function () {
-    return _defineProperty(this, bar, complex())[bar];
-  },
-  enumerable: true
-}));
+    enumerable: true,
+    configurable: true
+  }));
+
+  return Foo;
+})();
 
 var foo = Object.defineProperties({}, _defineProperty({
   bar: {
     get: function () {
       return _defineProperty(this, "bar", complex()).bar;
     },
-    enumerable: true
+    enumerable: true,
+    configurable: true
   }
 }, bar, {
   get: function () {
     return _defineProperty(this, bar, complex())[bar];
   },
-  enumerable: true
+  enumerable: true,
+  configurable: true
 }));

test/fixtures/transformation/source-maps/class/expected.js

@@ -5,16 +5,21 @@ var _prototypeProperties = function (child, staticProps, instanceProps) {
   if (instanceProps) Object.defineProperties(child.prototype, instanceProps);
 };
 
-var Test = function Test() {};
+var Test = (function () {
+  var Test = function Test() {};
 
-_prototypeProperties(Test, null, {
-  bar: {
-    get: function () {
-      throw new Error("wow");
-    },
-    enumerable: true
-  }
-});
+  _prototypeProperties(Test, null, {
+    bar: {
+      get: function () {
+        throw new Error("wow");
+      },
+      enumerable: true,
+      configurable: true
+    }
+  });
+
+  return Test;
+})();
 
 var test = new Test();
 test.bar;

test/fixtures/transformation/source-maps/class/source-mappings.json

@@ -4,7 +4,7 @@
     "column": 10
   },
   "generated": {
-    "line": 13,
-    "column": 13
+    "line": 14,
+    "column": 15
   }
 }]

test/fixtures/transformation/spec-setters/class-no-args/actual.js

@@ -0,0 +1,5 @@
+class Foo {
+  set bar() {
+
+  }
+}

test/fixtures/transformation/spec-setters/class-two-args/actual.js

@@ -0,0 +1,5 @@
+class Foo {
+  set bar(foo, bar) {
+
+  }
+}

test/fixtures/transformation/spec-setters/object-no-args/actual.js

@@ -0,0 +1,5 @@
+var obj = {
+  set bar() {
+
+  }
+};

test/fixtures/transformation/spec-setters/object-two-args/actual.js

@@ -0,0 +1,5 @@
+var obj = {
+  set bar(foo, bar) {
+
+  }
+};

test/fixtures/transformation/spec-setters/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Setters must have only one parameter"
+}